clinical whole exome sequencing

  • 文章类型: Journal Article
    使用临床全外显子组测序(WES)确定一对夫妇单基因遗传性疾病的遗传原因,并就他们的生殖选择提供建议。
    WES适用于一对寻求生殖建议的夫妇,女性身材矮小,男性患有先天性白内障。
    (1)该女子在chrX:591590-605428(hg19)处表现出13.8Kb的杂合缺失。该区域对应于含有矮小同源异型盒(SHOX)基因(NM000451)的外显子2-6。涉及SHOX基因的相关疾病范围从严重的Leri-Weill软骨发育不良到轻度非特异性身材矮小。同时,使用定量逆转录聚合酶链反应测定的进一步验证证实了先证者中SHOX基因的杂合缺失,以及其他具有相似临床特征的家庭成员(先证者的母亲,阿姨,和表弟)。HGMD数据库中已包含该变体的多种致病报告。根据美国医学遗传学和基因组学学院(ACMG)分类标准,这种缺失被归类为致病性。(2)对于男性患者,在CRYBB3基因中检测到杂合变体:NM004076:c.226G>A(p。Gly76R)。CRYBB3基因的变异可引起白内障22(OMIM:609741)。目前,该变异基因座不包括在数据库中,如gnomAD,而SIFT和PolyPhen2都认为这个地方“有害”。此外,通过Sanger测序的进一步验证证实该变异体遗传自男性患者的母亲,也有白内障。根据ACMG标准和指南,c.226G>A(p。CRYBB3基因中的Gly76Arg)变体被分类为具有“不确定的意义”。
    WES在两个个体中都发现了致病变异,表明健康孩子自然有25%的机会。建议使用第三代辅助生殖技术,以最大程度地减少受影响后代的风险。
    UNASSIGNED: To determine the genetic causes of monogenic inherited diseases in a couple using clinical whole exome sequencing (WES) and advise on their reproductive choices.
    UNASSIGNED: WES was applied to a couple seeking reproductive advice, the female with short stature and the male with congenital cataracts.
    UNASSIGNED: (1) The woman exhibited a 13.8 Kb heterozygous deletion at chrX: 591590-605428 (hg19). This region corresponds to exons 2-6 of the short-stature homeobox-containing (SHOX) gene (NM000451). Associated diseases involving the SHOX gene range from severe Leri-Weill dyschondrosteosis to mild nonspecific short stature. Meanwhile, further validation using a quantitative reverse transcription polymerase chain reaction assay confirmed the heterozygous deletion of the SHOX gene in the proband, as well as other family members with similar clinical characteristics (the proband\'s mother, aunt, and cousin). Multiple pathogenic reports of this variant have been included in the HGMD database. Per the American College of Medical Genetics and Genomics (ACMG) classification criteria, this deletion is classified as pathogenic. (2) For the male patient, a heterozygous variant was detected in the CRYBB3 gene: NM004076: c.226G>A (p.Gly76R). Variants in the CRYBB3 gene can cause Cataract 22 (OMIM: 609741). At present, this variant locus is not included in databases such as the gnomAD, while both SIFT and PolyPhen2 deem this locus \'damaging\'. Moreover, further validation by Sanger sequencing confirmed that the variant was inherited from the male patient\'s mother, who also had cataracts. According to ACMG standards and guidelines, the c.226G>A (p.Gly76Arg) variant in the CRYBB3 gene is classified as having \'uncertain significance\'.
    UNASSIGNED: WES identified pathogenic variants in both individuals, suggesting a 25% chance of a healthy child naturally. Third-generation assisted reproductive techniques are recommended to minimize the risk of affected offspring.
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  • 文章类型: Case Reports
    白细胞介素2受体α链(IL-2Rα或CD25)缺乏(OMIM#606367)是一种以常染色体隐性形式分离的免疫失调病症。该疾病是由编码IL-2Rα(也称为CD25蛋白)的IL-2Rα基因中的双等位基因变体引起的。IL-2Rα与白介素2受体的γ和β链结合形成功能性白介素2受体(IL-2R)。在本研究中,我们确定了一个呈现独特的IL-2Rα缺乏症的巴基斯坦家庭。临床全外显子组测序揭示了IL-2Rα基因中的新型剪接供体位点变体(NM_001378789.1(NP_001365718);c.64+1G>A)。美国医学遗传学学会(ACMG)指南将鉴定的变异解释为可能的致病性。IL-2Rα基因突变通常表现为自身免疫和免疫缺陷,但在我们的患者中,它表现为先天性腹泻,代谢危机,以及由于类似并发症而在婴儿期死亡的强烈家族史。她的先天性腹泻归因于自身免疫性肠病和湿疹形式的自身免疫。实验室发现显示严重的代谢性酸中毒低钾血症以及乳酸和氨水平升高。这是IL-2Rα基因突变的新表现。本研究强调了临床全外显子组测序在先天性疾病正确诊断中的重要性。该研究还将帮助临床遗传学家在受影响的家庭中进行遗传咨询和预防疾病。
    Interleukin 2 receptor alpha chain (IL-2Rα or CD25) deficiency (OMIM #606367) is an immune dysregulation disorder segregating in autosomal recessive form. The disease is caused by biallelic variants in the IL-2Rα gene encoding IL-2Rα also known as CD25 protein. IL-2Rα combines with γ and β chains of interleukin 2 receptor to form a functional interleukin 2 receptor (IL-2R). In the present study, we identified a Pakistani family presenting a unique presentation of IL-2Rα deficiency. Clinical whole exome sequencing revealed a novel splice donor site variant (NM_001378789.1 (NP_001365718); c.64 + 1G > A) in the IL-2Rα gene. American College of Medical Genetics (ACMG) guidelines interpreted the identified variant as likely pathogenic. The IL-2Rα gene mutation usually presents with autoimmunity and immunodeficiency but in our patient, it presents with congenital diarrhea, metabolic crisis, and strong family history of death in infancy due to the similar complications. Her congenital diarrhea is attributed to autoimmunity in the form of autoimmune enteropathy and eczema. The laboratory findings revealed severe metabolic acidosis hypokalemia and elevated lactate and ammonia levels. This is a new presentation of IL-2Rα gene mutation. The present study highlights the importance of clinical whole exome sequencing in the correct diagnosis of congenital disorders. The study will also help clinical geneticists for genetic counseling and prevention of the disease in the affected family.
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